POP3 Protocol wrapper class

On the Internet, electronic mail (e-mail) is the most widely used application. According to experts, of all TCP connections that Internet users establish, about one-half are for sending and receiving e-mail messages. So it is impossible for any Internet programmer to leave this area.

Usually e-mail systems use SMTP as a mail sending Protocol and POP3 as a mail receiving Protocol. For details about these Protocols you can refere to RCF 821 (for SMTP) and RFC 1225 (for POP3). Since in Windows environment we have MAPI for e-mail handling but it do not provide enough power to commuincate with e-mail server directly.

Here I developed a class for POP 3 protocol. In this class I used CSocket as class member (surperise not inherent it), so that I can used it in Threads. POP Class has methods which are resembled with POP 3 protocol commands. Following is code of the class with comments.

/*--------------------------------------------------------------------
     Pop.h : main header file for the POP application
-----------------------------------------------------------------------*/

#if !defined(AFX_POP_H__A44B38B6_697C_11D1_881E_00001C302581__INCLUDED_)
#define AFX_POP_H__A44B38B6_697C_11D1_881E_00001C302581__INCLUDED_

#define CONNECTION_CHECK 0
#define USER_CHECK  1
#define PASSWORD_CHECK 2
#define QUIT_CHECK  3
#define DELETE_CHECK 4
#define RSET_CHECK  5
#define STAT_CHECK  6
#define NOOP_CHECK  7
#define LIST_CHECK  8
#define RETR_CHECK  9

/////////////////////////////////////////////////////////////////////////////
class CPop
{
public:
 BOOL List();
 CWordArray m_SizeOfMsg;
 CString GetErrorMessage();    // If there is any error this will return it method
 CString GetPassword();           // Getting Password stored in class
 void SetPassword(CString& Password);    // Setting Password in class
 CString GetUser();                   // Getting user name stored in class
 void SetUser(CString& User);  // Setting user name in class
 CString GetHost();                    // Getting Host name (email server name) stored in class
 void SetHost(CString& Host);    // Setting Host name (email server name) in class
 BOOL Connect();                    // Connecting to email server
 int GetTotalMailSize();                // it returns the Total Mail Size
 int GetNumberOfMails();            // It return the number of mails
 CString GetMsgContents();        
 BOOL Statistics();                    // issue the STAT command on email server
 BOOL Retrieve(int MsgNumber);    // Getting any particular mail message
 BOOL Reset();                        // issue the reset command on email server
 int  GetMessageSize(int MsgNumber);    // Return a size of any particular mail
 BOOL Noop();                     // issue the NOOP command on email server
 BOOL Disconnect();            // issue the QUIT command on email server
 BOOL Delete(int& MsgNumber); // Deleteing a particular message from email server
 BOOL Connect(CString& Host, CString& User, CString& Password);
 CPop();
 virtual ~CPop();

private:
 CString m_ErrorMessage;
 BOOL CheckResponse(int ResponseType);
 CString m_Password;
 CString m_User;
 CString m_Host;
 CString m_MsgContents;
 int m_TotalSize;
 int m_NumberMail;
 CSocket m_PopServer;
};
/#endif // !defined(AFX_POP_H__A44B38B6_697C_11D1_881E_00001C302581__INCLUDED_)
 

/*-----------------------------------------------------------------------------------------------
// Pop.cpp : Defines the class behaviors for the application.
---------------------------------------------------------------------------------------------------*/

#include "stdafx.h"
#include "Pop.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

////////////////////////////////////////////////////////////////////
// CPop Class
//////////////////////////////////////////////////////////////////////

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

CPop::CPop()
{
 m_PopServer.Create();
}
//{4EEC1C91-6BE1-11d1-8824-00001C302581}

CPop::~CPop()
{
 m_PopServer.Close();
}

BOOL CPop::Connect(CString & Host, CString & User, CString & Password)
{
 char buf [512];

 if (!m_PopServer.Connect(Host,110)) // 110 Pop3 Port
 {
  m_ErrorMessage = _T("Server cannot be connected");
  return FALSE;
 }
 else
 {
  if(CheckResponse(CONNECTION_CHECK)==FALSE)
   return FALSE;

  wsprintf (buf, "USER %s\r\n", (LPCSTR) User);
  m_PopServer.Send(buf, strlen (buf));
  if(CheckResponse(USER_CHECK)==FALSE)
   return FALSE;

  wsprintf (buf, "PASS %s\r\n", (LPCSTR) Password);
  m_PopServer.Send(buf, strlen (buf));
  if (CheckResponse(PASSWORD_CHECK)==FALSE)
   return FALSE;

  return TRUE;
 }

}

BOOL CPop::Delete(int & MsgNumber)
{
 char buf [512];

 wsprintf (buf, "DELE %d\r\n",MsgNumber );
 m_PopServer.Send(buf, strlen (buf));
 if (CheckResponse(DELETE_CHECK)==FALSE)
  return FALSE;
 else
  return TRUE;
}

BOOL CPop::Disconnect()
{
 char buf [512];

 wsprintf (buf, "QUIT \r\n");
 m_PopServer.Send(buf, strlen (buf));
 if (CheckResponse(QUIT_CHECK)==FALSE)
  return FALSE;
 else
  return TRUE;
}

BOOL CPop::Noop()
{
 char buf [512];

 wsprintf (buf, "NOOP  \r\n");
 m_PopServer.Send(buf, strlen (buf));
 if (CheckResponse(NOOP_CHECK)==FALSE)
  return FALSE;
 else
  return TRUE;
}

// Return the Msg Size for given msg number
int CPop::GetMessageSize(int MsgNumber)
{
 if(m_SizeOfMsg.GetSize() < MsgNumber+1)
  return 0;
 else
  return m_SizeOfMsg[MsgNumber+1];
}

BOOL CPop::Reset()
{
 char buf [512];

 wsprintf (buf, "RSET \r\n");
 m_PopServer.Send(buf, strlen (buf));
 if (CheckResponse(RSET_CHECK)==FALSE)
  return FALSE;
 else
  return TRUE;
}

// MsgContents will hold the msg body
BOOL CPop::Retrieve(int  MsgNumber)
{
 char buf [512];

 wsprintf (buf, "RETR %d\r\n",MsgNumber );
 m_PopServer.Send(buf, strlen (buf));
 if (CheckResponse(RETR_CHECK)==FALSE)
  return FALSE;
 else
  return TRUE;
}

BOOL CPop::Statistics()
{
 char buf [512];

 wsprintf (buf, "STAT \r\n");
 m_PopServer.Send(buf, strlen (buf));
 if (CheckResponse(STAT_CHECK)==FALSE)
  return FALSE;
 else
  return TRUE;
}

CString CPop::GetMsgContents()
{
 return m_MsgContents;
}

int CPop::GetNumberOfMails()
{
 return m_NumberMail;
}

int CPop::GetTotalMailSize()
{
 return m_TotalSize;
}

BOOL CPop::Connect()
{
 Connect(m_Host, m_User, m_Password);
 return TRUE;
}

void CPop::SetHost(CString & Host)
{
 m_Host = Host;
}

CString CPop::GetHost()
{
 return m_Host;
}

void CPop::SetUser(CString & User)
{
 m_User = User;
}

CString CPop::GetUser()
{
 return m_User;
}

void CPop::SetPassword(CString & Password)
{
 m_Password = Password;
}

CString CPop::GetPassword()
{
 return m_Password;
}

BOOL CPop::CheckResponse(int ResponseType)
{
 char buf [1000];

 for (int i=0;i<512;i++)
  buf[i]='\0';

 m_PopServer.Receive(buf, sizeof(buf));

 switch (ResponseType)
 {
  case CONNECTION_CHECK:
   if (strnicmp(buf,"-ERR", 4) == 0)
   {
    m_ErrorMessage = _T("Bad Connection");
    return FALSE;
   }
   break;

  case USER_CHECK:
   if (strnicmp(buf,"-ERR", 4) == 0)
   {
    m_ErrorMessage = _T("Bad User Name");
    return FALSE;
   }
   break;
  case PASSWORD_CHECK:
   if (strnicmp(buf,"-ERR", 4) == 0)
   {
    m_ErrorMessage = _T("Bad Password Name");
    return FALSE;
   }
   break;
  case QUIT_CHECK:
   if (strnicmp(buf,"-ERR", 4) == 0)
   {
    m_ErrorMessage = _T("Error occured during QUIT");
    return FALSE;
   }
   break;
  case DELETE_CHECK:
   if (strnicmp(buf,"-ERR", 4) == 0)
   {
    m_ErrorMessage = _T("Error occured during DELE");
    return FALSE;
   }
   break;
  case RSET_CHECK:
   if (strnicmp(buf,"-ERR", 4) == 0)
   {
    m_ErrorMessage = _T("Error occured during RSET");
    return FALSE;
   }
   break;
  case STAT_CHECK:
   if (strnicmp(buf,"-ERR", 4) == 0)
   {
    m_ErrorMessage = _T("Error occured during STAT");
    return FALSE;
   }
   else
   {
    BOOL EmailNumber = TRUE;
    for (char *p = buf; *p != '\0'; p++)
    {
     if (*p == '\t' || *p == ' ')
     {
      if(EmailNumber == TRUE)
      {
       m_NumberMail = atoi(p);
       EmailNumber = FALSE;
      }
      else
      {
       m_TotalSize = atoi(p);
       return TRUE;
      }
     }
    }

   }
   break;
  case NOOP_CHECK:
   if (strnicmp(buf,"-ERR", 4) == 0)
   {
    m_ErrorMessage = _T("Error occured during NOOP");
    return FALSE;
   }
   break;

  case LIST_CHECK:
   if (strnicmp(buf,"-ERR", 4) == 0)
   {
    m_ErrorMessage = _T("Error occured during LIST");
    return FALSE;
   }
   else
   {
    m_PopServer.Receive(buf, sizeof(buf));

    for (char *p = buf; *p != '.'; p++)
     if (*p == '\t' || *p == ' ')
      m_SizeOfMsg.Add(atoi(p));
   }
   break;
  case RETR_CHECK:
   if (strnicmp(buf,"-ERR", 4) == 0)
   {
    m_ErrorMessage = _T("Error occured during RETR");
    return FALSE;
   }
   else
   {
    char temp[9000];
    m_PopServer.Receive(temp, sizeof(temp));
    m_MsgContents = temp;
   }
   break;
 }
 return TRUE;
}

CString CPop::GetErrorMessage()
{
 return m_ErrorMessage;
}

BOOL CPop::List()
{
 char buf [512];

 wsprintf (buf, "LIST  \r\n");
 m_PopServer.Send(buf, strlen (buf));
 if (CheckResponse(LIST_CHECK)==FALSE)
  return FALSE;
 else
  return TRUE;
}